Toroidal Multi-Segmented Lawn Mower Blade Noise Reduction

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Solution Overview

Problem

Conventional lawn mower cutting blades consume excessive energy and generate significant noise, particularly when powered by electric motors, which limits the runtime of battery-powered mowers and disturbs operators.

Innovation Solution

The design of a lawn mower cutting blade featuring a hub with elongate arms forming a toroidal shape, where each arm extends outwardly and then loops back to the hub, creating a cutting surface that reduces noise and energy consumption by optimizing the cutting mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional cutting blades are used, then cutting function is achieved, but noise in the 2-5 kHz range increases and energy consumption increases

Engineering Contradiction:

ImprovenoiseVSAvoidenergy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The cutting blade is divided into multiple discrete segments or elements arranged in a toroidal configuration, where each segment can be independently optimized for cutting performance while contributing to overall noise reduction through distributed cutting action rather than a single continuous blade edge

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cutting blade employs a toroidal (doughnut-shaped) geometry with curved cutting surfaces instead of conventional flat or linear blade designs, creating a three-dimensional cutting path that reduces noise by distributing cutting forces and minimizing vibration in the 2-5 kHz frequency range

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Duration of action of moving object

If conventional cutting blades are used, then cutting function is achieved, but runtime of battery-powered mowers is limited

Engineering Contradiction:

ImproveruntimeVSAvoidenergy consumption

Core Design Contradiction:

Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The toroidal cutting blade incorporates dynamic elements that allow the cutting segments to adjust their position or orientation during rotation, optimizing cutting efficiency at different rotational speeds and reducing energy consumption to extend battery-powered mower runtime

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The blade design changes key operational parameters including cutting speed distribution, contact pressure with vegetation, and rotational dynamics to reduce overall energy consumption while maintaining effective cutting performance throughout the battery charge cycle

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If conventional cutting blades are used, then cutting function is achieved, but operational noise disturbs operators

Engineering Contradiction:

Improveoperational comfortVSAvoidoperational noise

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The toroidal geometry with its smooth curved surfaces and three-dimensional cutting path significantly reduces operational noise in the disturbing 2-5 kHz frequency range, improving operator comfort while maintaining effective cutting function

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS20240349642A1Multi-segmented lawn mower cutting blade and lawn mower including same

Publication Date: 2024.10.24 EXMARK MFG CO INC

AI summary

A multi-segmented lawn mower cutting blade and lawn mower including same. The blade may include a hub defining a rotational blade axis and an elongate arm. The arm includes: an origin connected to the hub; a first segment extending outwardly away from the hub in a first direction from the origin to a distal end of the first segment; and a second segment extending from the distal end of the first segment in a second direction, the second direction being different than the first direction. At least a portion of the arm forms a cutting surface configured to cut vegetation as the blade rotates about the blade axis.